This invention relates to a battery charger circuit, and more specifically to a battery charger circuit having means therein for periodically discharging the battery during the charging process to increase the rate of battery charge acceptance.
Recent advancements in the field of battery charger circuits include the discovery that rate of battery charge acceptance may be increased through periodic battery discharge during the charging process. By periodically discharging the battery through high current discharge pulses during the charging process, charging time may be drastically reduced in comparison with the charging time required by use of conventional charging methods.
One such battery charging circuit for periodically producing high current battery discharge pulses is disclosed in U.S. Pat. No. 3,816,806 issued June 11, 1974 to Joseph Mas. High current battery discharge pulses are generated according to the Mas patent by causing a high current transistor, serially connected with a relatively low resistance and the battery under charge, to conduct, thus diverting charge current and causing high current power pulses supplied by the sum of charge current and battery discharge current to be dissipated in the resistance. When the high current transistor is nonconductive, the battery receives undiverted charge current from the current source, thus continuing the charging process.
A disadvantage of the battery charger circuit disclosed by Mas is that the discharge power pulse is dissipated is the resistance, thus generating power losses. As the frequency of discharge increases, these losses become substantial, resulting in inefficient operation.
The battery charger according to the teaching of the present invention alleviates the disadvantage of discharge energy being dissipated through a resistive element. The present invention contemplates a battery charger circuit in which battery discharge energy is stored for later return to the battery during the charging cycle.